Combustor temperatures in gas turbine engines can reach extreme heights. The air temperature in a combustor often exceeds the melting point of the combustor liner. Combustors often have “dilution holes” in the liner. Dilution holes allow combustors to operate at conditions that minimize emissions generated during the combustion process. In addition, dilution holes promote mixing within the combustion chamber, which serves to condition the flow entering the turbine. Combustion dilution holes are often disposed at locations that are difficult to cool. The dilution holes may also have separations within the dilution holes that tend to entrain hot gas produce localized hot spots. The hot spots can damage the dilution holes themselves, as well as the surrounding combustor liner.
Dilution hole and distress may alter the intended shape of the holes, which may impact the level of emissions generated by the combustor. Such distress may also impact the mixing of flow before the flow enters the high pressure turbine portion of the engine. Inadequate mixing of flow entering the turbine may cause distress on turbine hardware. Additionally, combustor liner and dilution hole distress may negatively impact overall engine efficiency.
Dilution holes are typically not designed to actively cool the surrounding combustor liner. Cooling features surrounding the dilution hole may be used to actively cool the area immediately surrounding the dilution hole. Conventional cooling techniques used around dilution holes rely on drilling discrete cooling holes, which may not be able to provide adequate cooling to the combustor liner. Novel ways to cool the area immediately surrounding dilution holes may extend the life of combustor and turbine hardware, as well as contribute positively to combustion emissions and overall engine performance.